This invention relates to an apparatus and method for transferring vehicle bodies that hang and transfer vehicle bodies, and more particularly to an apparatus and method for transferring vehicle bodies that make a hang condition of the vehicle bodies stable.
On an automotive assembly line, a plurality of vehicle body transfer apparatuses are used as corresponding to parts to be mounted, and positions in the vehicle bodies where the parts are mounted, to transfer the vehicle bodies and mount various parts. As such vehicle body transfer apparatuses, for example, an overhead conveyor or the like is used to mount parts to be attached from underside in the vehicle bodies, while a friction conveyor is used to mount an interior parts or the like in the vehicle bodies. The overhead conveyor supports the vehicle body using a hanger suspended on a transfer rail, and moves the hanger along the transfer rail. The hanger includes four arms in right and left sides of front and rear positions, and supports the vehicle body at four spots in right and left sides of front and rear portions thereof with vehicle body support parts of the four arms. The friction conveyor places the vehicle body on each pallet, and moves the pallet along the transfer rail. If the vehicle body is attached with tires, the tires are directly placed on the pallet, but if the vehicle body is not attached with tires, the bottom portion of the vehicle body is placed on the vehicle body support parts.
On the automotive assembly line, not only vehicle bodies of a single vehicle type, but also vehicle bodies of various vehicle types are assembled. Therefore, the vehicle body transfer apparatus such as the overhead conveyor is required to transfer vehicle bodies each having different total length and weight. For example, Japanese Laid-Open Patent Application, Publication No. 2-117508 discloses a vehicle transfer apparatus that holds front and rear wheels of a vehicle, and hangs and transfers the vehicle. This vehicle transfer apparatus includes a mechanism that may move any one of a front-wheel holding member and a rear-wheel holding member in front and rear directions, and may thus transfer vehicles having different wheel bases.
However, the overhead conveyor supports the vehicle body by hanging the same, and is thus likely to have difficulty in maintaining stability of the vehicle body during transfer in comparison with a friction conveyor that transfers the vehicle body by placing the vehicle body thereon. Further, as discussed above, the total length, weight, or the like of the vehicle body varies with the types of the vehicles, and thus the weight balance of the vehicle body varies with the types of the vehicles. Therefore, if the vehicle bodies of various vehicle types having different weight balance were supported using a hanger having immovable arms provided on right and left sides of front and rear portions of the vehicle body, the stability of the vehicle bodies during transfer would get worse. In particular, when the transfer direction of the overhead conveyor is inclined upward or downward due to the factory layout or the like, the vehicle bodies supported with the hangers are transferred in a vertically inclined posture. Consequently, among overhead conveyors are those having a hanger that moves the arms"" positions in front, rear, right, and left directions according to the type of the vehicle body (i.e., the whole length and/or weight balance of the vehicle body), and support the vehicle body, in order to secure stability of the vehicle body. In that event, the hanger needs a complex mechanism for moving the arms in front, rear, right, and left directions.
Therefore, it is an object of the present invention to provide an apparatus and method for transferring vehicle bodies that can stably transfer the vehicle bodies of various vehicle types with a simple structure.
An apparatus for transferring vehicle bodies according to the present invention, which can achieve the above object, is that which hangs and transfers a vehicle body of every vehicle type. The apparatus comprises a hang-and-transfer means that supports the vehicle body in a hanging condition, and moves along a transfer path, and a position adjustment means that adjusts supporting positions on the vehicle body in the hang-and-transfer means based upon a center of gravity of the vehicle body of each vehicle type.
According to this apparatus for transferring vehicle bodies, the position adjustment means moves the vehicle body frontward and rearward to a position in which a center of gravity of the vehicle body of every vehicle type and a center of the hang-and-transfer means are aligned or substantially aligned with each other. Therefore, the apparatus for transferring vehicle bodies may support the vehicle body in a well-weight-balanced condition in the hang-and-transfer means, and thus may stably transfer the vehicle body.
Moreover, in the above apparatus for transferring vehicle bodies, the hang-and-transfer means may include center-of-gravity management plates each having a plurality of vehicle body support parts that support the vehicle body according to the vehicle type of the vehicle body.
According to this apparatus for transferring vehicle bodies, distances between the vehicle body support parts of the center-of-gravity management plates each provided on the arms at right and left sides of front and rear portions of the hang-and-transfer means vary with the vehicle type of the vehicle body. Therefore, this apparatus for transferring vehicle bodies allows the vehicle body support parts to support the vehicle body according to the vehicle type of the vehicle body, and thereby the center of gravity of the vehicle body of every vehicle type and the center of the hang-and-transfer means may be aligned or substantially aligned with each other. Consequently, variations in the total length and/or weight balance according to the vehicle type would not require any mechanism for moving positions of the arms of the hang-and-transfer means in the front, rear, right, and left directions, which thus serves to simplify the structure of the hang-and-transfer means adaptable to varying vehicle types.
A method for transferring vehicle bodies according to the present invention, which can achieve the above object, is that which hangs and transfers a vehicle body of every vehicle type. The method includes a position adjustment step of adjusting supporting positions on the vehicle body in a hang-and-transfer means based upon a center of gravity of the vehicle body of each vehicle type, which hang-and-transfer means supports the vehicle body in a hanging condition and moves along a transfer path.
According to this method for transferring vehicle bodies, in the position adjustment step, the vehicle body is moved frontward and rearward to a position at which the center of gravity of the vehicle body of every vehicle type and a center of the hang-and-transfer means are aligned or substantially aligned with each other. Therefore, this method for transferring vehicle bodies may serve to support the vehicle body in a well-weight-balanced condition in the hang-and-transfer means, and thus may serve to stably transfer the vehicle body.
Moreover, in the above method for transferring vehicle bodies, the hang-and-transfer means may include center-of-gravity management plates each having a plurality of vehicle body support parts that support the vehicle body according to the vehicle type of the vehicle body, and the position adjustment step may allow the vehicle body support part to place the vehicle body according to the vehicle type.
According to this method for transferring vehicle bodies, distances between the body support parts of the center-of-gravity management plates each provided on the arms at right and left sides of front and rear portions of the hang-and-transfer means vary with the vehicle type of the vehicle body. Therefore, this method for transferring vehicle bodies allows the vehicle body support parts to support the vehicle body according to the vehicle type of the vehicle body, and thereby the center of gravity of the vehicle body of every vehicle type and the center of the hang-and-transfer means may be aligned or substantially aligned with each other. Consequently, changes in the total length and/or weight balance according to the vehicle type would not require any mechanism for moving positions of the arms of the hang-and-transfer means in the front, rear, right, and left directions, which thus serves to simplify the structure of the hang-and-transfer means adaptable to varying vehicle types.
Other objects and further features of the present invention will become readily apparent from the following description of preferred embodiments with reference to accompanying drawings.